﻿/*
Copyright(c) 2008 Casey Duncan

Permission is hereby granted, free of charge, to any person obtaining a copy
of this software and associated documentation files (the "Software"), to deal
in the Software without restriction, including without limitation the rights
to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
copies of the Software, and to permit persons to whom the Software is
furnished to do so, subject to the following conditions:

The above copyright notice and this permission notice shall be included in all
copies or substantial portions of the Software.

THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
SOFTWARE.
*/

using UnityEngine;

namespace Cubizer.Math
{
	public static class Noise
	{
		public static float F2 = 0.3660254037844386f;
		public static float G2 = 0.21132486540518713f;
		public static float F3 = 1.0f / 3.0f;
		public static float G3 = 1.0f / 6.0f;

		public static float[,] GRAD3 = new float[16, 3]
		{
				{ 1, 1, 0 }, { -1, 1, 0 }, { 1,-1, 0 }, {-1,-1, 0 },
				{ 1, 0, 1 }, { -1, 0, 1 }, { 1, 0,-1 }, {-1, 0,-1 },
				{ 0, 1, 1 }, { 0, -1, 1 }, { 0, 1,-1 }, { 0,-1,-1 },
				{ 1, 0,-1 }, { -1, 0,-1 }, { 0,-1, 1 }, { 0, 1, 1 }
		};

		public static byte[] PERM = new byte[]
		{
				151, 160, 137, 91, 90, 15, 131, 13,
				201, 95, 96, 53, 194, 233, 7, 225,
				140, 36, 103, 30, 69, 142, 8, 99,
				37, 240, 21, 10, 23, 190, 6, 148,
				247, 120, 234, 75, 0, 26, 197, 62,
				94, 252, 219, 203, 117, 35, 11, 32,
				57, 177, 33, 88, 237, 149, 56, 87,
				174, 20, 125, 136, 171, 168, 68, 175,
				74, 165, 71, 134, 139, 48, 27, 166,
				77, 146, 158, 231, 83, 111, 229, 122,
				60, 211, 133, 230, 220, 105, 92, 41,
				55, 46, 245, 40, 244, 102, 143, 54,
				65, 25, 63, 161, 1, 216, 80, 73,
				209, 76, 132, 187, 208, 89, 18, 169,
				200, 196, 135, 130, 116, 188, 159, 86,
				164, 100, 109, 198, 173, 186, 3, 64,
				52, 217, 226, 250, 124, 123, 5, 202,
				38, 147, 118, 126, 255, 82, 85, 212,
				207, 206, 59, 227, 47, 16, 58, 17,
				182, 189, 28, 42, 223, 183, 170, 213,
				119, 248, 152, 2, 44, 154, 163, 70,
				221, 153, 101, 155, 167, 43, 172, 9,
				129, 22, 39, 253, 19, 98, 108, 110,
				79, 113, 224, 232, 178, 185, 112, 104,
				218, 246, 97, 228, 251, 34, 242, 193,
				238, 210, 144, 12, 191, 179, 162, 241,
				81, 51, 145, 235, 249, 14, 239, 107,
				49, 192, 214, 31, 181, 199, 106, 157,
				184, 84, 204, 176, 115, 121, 50, 45,
				127, 4, 150, 254, 138, 236, 205, 93,
				222, 114, 67, 29, 24, 72, 243, 141,
				128, 195, 78, 66, 215, 61, 156, 180,
				151, 160, 137, 91, 90, 15, 131, 13,
				201, 95, 96, 53, 194, 233, 7, 225,
				140, 36, 103, 30, 69, 142, 8, 99,
				37, 240, 21, 10, 23, 190, 6, 148,
				247, 120, 234, 75, 0, 26, 197, 62,
				94, 252, 219, 203, 117, 35, 11, 32,
				57, 177, 33, 88, 237, 149, 56, 87,
				174, 20, 125, 136, 171, 168, 68, 175,
				74, 165, 71, 134, 139, 48, 27, 166,
				77, 146, 158, 231, 83, 111, 229, 122,
				60, 211, 133, 230, 220, 105, 92, 41,
				55, 46, 245, 40, 244, 102, 143, 54,
				65, 25, 63, 161, 1, 216, 80, 73,
				209, 76, 132, 187, 208, 89, 18, 169,
				200, 196, 135, 130, 116, 188, 159, 86,
				164, 100, 109, 198, 173, 186, 3, 64,
				52, 217, 226, 250, 124, 123, 5, 202,
				38, 147, 118, 126, 255, 82, 85, 212,
				207, 206, 59, 227, 47, 16, 58, 17,
				182, 189, 28, 42, 223, 183, 170, 213,
				119, 248, 152, 2, 44, 154, 163, 70,
				221, 153, 101, 155, 167, 43, 172, 9,
				129, 22, 39, 253, 19, 98, 108, 110,
				79, 113, 224, 232, 178, 185, 112, 104,
				218, 246, 97, 228, 251, 34, 242, 193,
				238, 210, 144, 12, 191, 179, 162, 241,
				81, 51, 145, 235, 249, 14, 239, 107,
				49, 192, 214, 31, 181, 199, 106, 157,
				184, 84, 204, 176, 115, 121, 50, 45,
				127, 4, 150, 254, 138, 236, 205, 93,
				222, 114, 67, 29, 24, 72, 243, 141,
				128, 195, 78, 66, 215, 61, 156, 180
		};

		public static float Noise2(float x, float y)
		{
			int i1, j1, I, J;
			float s = (x + y) * F2;
			float i = Mathf.Floor(x + s);
			float j = Mathf.Floor(y + s);
			float t = (i + j) * G2;

			float[] xx = new float[3], yy = new float[3], f = new float[3];
			float[] noise = new float[3] { 0.0f, 0.0f, 0.0f };
			int[] g = new int[3];

			xx[0] = x - (i - t);
			yy[0] = y - (j - t);

			i1 = xx[0] > yy[0] ? 1 : 0;
			j1 = xx[0] <= yy[0] ? 1 : 0;

			xx[2] = xx[0] + G2 * 2.0f - 1.0f;
			yy[2] = yy[0] + G2 * 2.0f - 1.0f;
			xx[1] = xx[0] - i1 + G2;
			yy[1] = yy[0] - j1 + G2;

			I = (int)i & 255;
			J = (int)j & 255;
			g[0] = PERM[I + PERM[J]] % 12;
			g[1] = PERM[I + i1 + PERM[J + j1]] % 12;
			g[2] = PERM[I + 1 + PERM[J + 1]] % 12;

			for (byte c = 0; c <= 2; c++)
			{
				f[c] = 0.5f - xx[c] * xx[c] - yy[c] * yy[c];
			}

			for (byte c = 0; c <= 2; c++)
			{
				if (f[c] > 0)
				{
					noise[c] = f[c] * f[c] * f[c] * f[c] * (GRAD3[g[c], 0] * xx[c] + GRAD3[g[c], 1] * yy[c]);
				}
			}

			return (noise[0] + noise[1] + noise[2]) * 70.0f;
		}

		public static float Noise3(float x, float y, float z)
		{
			int I, J, K;
			int[] o1 = new int[3], o2 = new int[3], g = new int[4];
			float[] f = new float[4], noise = new float[4] { 0.0f, 0.0f, 0.0f, 0.0f };
			float s = (x + y + z) * F3;
			float i = Mathf.Floor(x + s);
			float j = Mathf.Floor(y + s);
			float k = Mathf.Floor(z + s);
			float t = (i + j + k) * G3;

			float[,] pos = new float[4, 3];

			pos[0, 0] = x - (i - t);
			pos[0, 1] = y - (j - t);
			pos[0, 2] = z - (k - t);

			if (pos[0, 0] >= pos[0, 1])
			{
				if (pos[0, 1] >= pos[0, 2])
				{
					o1[0] = 1; o1[1] = 0; o1[1] = 0;
					o2[0] = 1; o2[1] = 1; o2[1] = 0;
				}
				else if (pos[0, 0] >= pos[0, 2])
				{
					o1[0] = 1; o1[1] = 0; o1[1] = 0;
					o2[0] = 1; o2[1] = 0; o2[1] = 1;
				}
				else
				{
					o1[0] = 0; o1[1] = 0; o1[1] = 1;
					o2[0] = 1; o2[1] = 0; o2[1] = 1;
				}
			}
			else
			{
				if (pos[0, 1] < pos[0, 2])
				{
					o1[0] = 0; o1[1] = 0; o1[1] = 1;
					o2[0] = 0; o2[1] = 1; o2[1] = 1;
				}
				else if (pos[0, 0] < pos[0, 2])
				{
					o1[0] = 0; o1[1] = 1; o1[1] = 0;
					o2[0] = 0; o2[1] = 1; o2[1] = 1;
				}
				else
				{
					o1[0] = 0; o1[1] = 1; o1[1] = 0;
					o2[0] = 1; o2[1] = 1; o2[1] = 0;
				}
			}

			for (byte c = 0; c <= 2; c++)
			{
				pos[3, c] = pos[0, c] - 1.0f + 3.0f * G3;
				pos[2, c] = pos[0, c] - o2[c] + 2.0f * G3;
				pos[1, c] = pos[0, c] - o1[c] + G3;
			}

			I = (int)i & 255;
			J = (int)j & 255;
			K = (int)k & 255;
			g[0] = PERM[I + PERM[J + PERM[K]]] % 12;
			g[1] = PERM[I + o1[0] + PERM[J + o1[1] + PERM[o1[2] + K]]] % 12;
			g[2] = PERM[I + o2[0] + PERM[J + o2[1] + PERM[o2[2] + K]]] % 12;
			g[3] = PERM[I + 1 + PERM[J + 1 + PERM[K + 1]]] % 12;

			for (byte c = 0; c <= 3; c++)
			{
				f[c] = 0.6f - pos[c, 0] * pos[c, 0] - pos[c, 1] * pos[c, 1] -
					pos[c, 2] * pos[c, 2];
			}

			for (byte c = 0; c <= 3; c++)
			{
				if (f[c] > 0)
				{
					noise[c] = f[c] * f[c] * f[c] * f[c] * (pos[c, 0] * GRAD3[g[c], 0] + pos[c, 1] * GRAD3[g[c], 1] + pos[c, 2] * GRAD3[g[c], 2]);
				}
			}

			return (noise[0] + noise[1] + noise[2] + noise[3]) * 32.0f;
		}

		public static float Simplex2(float x, float y, int octaves, float persistence, float lacunarity)
		{
			float freq = 1.0f;
			float amp = 1.0f;
			float max = 1.0f;
			float total = Noise2(x, y);

			for (int i = 1; i < octaves; i++)
			{
				freq *= lacunarity;
				amp *= persistence;
				max += amp;
				total += Noise2(x * freq, y * freq) * amp;
			}

			return (total / max) * 0.5f + 0.5f;
		}

		public static float Simplex3(float x, float y, float z, int octaves, float persistence, float lacunarity)
		{
			float freq = 1.0f;
			float amp = 1.0f;
			float max = 1.0f;
			float total = Noise3(x, y, z);

			for (int i = 1; i < octaves; ++i)
			{
				freq *= lacunarity;
				amp *= persistence;
				max += amp;
				total += Noise3(x * freq, y * freq, z * freq) * amp;
			}

			return (1 + total / max) / 2;
		}

		public static void SimplexSeed(int seed)
		{
			UnityEngine.Random.InitState(seed);

			for (int i = 0; i < 256; i++)
				PERM[i] = (byte)i;

			for (int i = 255; i > 0; i--)
			{
				int j;
				int n = i + 1;
				while (n <= (j = (int)(UnityEngine.Random.Range(0.0f, float.MaxValue) / (float.MaxValue / n)))) { }
				byte a = PERM[i];
				byte b = PERM[j];
				PERM[i] = b;
				PERM[j] = a;
			}

			System.Buffer.BlockCopy(PERM, 0, PERM, 256, 255);
		}
	}
}